Typewriting machine



w. F. HELMON 2,226,931

TYPEWRITING MACHINE Filed Sept. 14, 1937' 5 Sheets-Sheet 1 Dec. 31, 1940.

I nvern tor:

B w tlorney.

Dec. 3l, i940. w. F. HELMOND TYPEWRITING MACHINE Filed Sept. 14, 1957 5 SheetSs-SheefI 2 f lllllqlll ll'llllllllllllllll/ Inventor:

Niamey.

Dec. 3l, 1940. w. F. HELMOND 2,226,931v

TYPEWRITING MACHINE Filed Sept. 14, 1957 5 Sheets-Sheet 3 Inventor;

Dec.- 31, 1940. w HELMOND 2,226,931

TYPEWRITING- MACHINE Filed Sept. 14, 1.937 5 Sheets-Sheet 4 1 vAlf'zorney.`

Dec. 31, 1940. w. F. HELMOND 2,226,931

TYPEWRITING MACHINE Filed Sept. 14, 1937 5 SheetS--Sheel 5 Inventor:

i I l I Attorney.

Patented- Dec. 3l, 1940 UNITED STATES TYPEWRITIN G MACHINE William F. Helmond, West Hartford, Conn., as-

signor to Underwood Elliott Fisher Company, New York, N. Y., a corporation ot Delaware Application September 14, 1937, Serial No. 163,739

1o claims. This invention relates to typewriting machines of the standard or heavy duty type, and more' .particularly to case-shifting mechanisms eilective by shifting the type-bar basket, and to im- 5 provements in the mounting and guiding means for the type-basket and case-shifting stops therefor, to render the machine comparatively quiet in operation.

The invention aims to increase the operating yl) eiiiciency of the typewriter by providing a caseshift mechanism operable with a minimum of eil'ort on the part of the operator, the mechanism being so arranged in relation to the type-bar segment that the operator need exert only a slight 6 pressure on the shift-key to control the raising and lowering of the segment in case-shifting, the invention also providing an improved case-shift stop affording dependable means for accurately positioning the upper and lower type relative to il) the platen, the case-shift mechanism and stop both co-operating to bring the segment to either position without imparting noise or impact to the machine.

The invention provides a case-shift mechanism l5 operable to lower the normally raised type basket,

the mechanism including a pair of toggles operating in tandem at each end'of the segment, the arms of which being in substantial alignment hold the type basket in normally raised position yand which, upon being actuated by either theshiftlever or the shift-lock lever are caused to fold, thereby owring the type-bar assembly, against the A, ually increasing tension of a eooperating return spring. The shift-lock lever, operating either in unison with, or independent of the shift-lever, has connected thereto, the mentioned return spring, the

same being of adequate power to cause the togglev mechanism to return to normal aligned condition, 0 thereby raising the type basket to its normal po-A sition; the effort of the operator being only that required to release "'a stop Dawl by depressing -the shift-lever, the operator thereafter serving only to control the raising vol? the type basket by al- 5 lowing the shiftkey to rise 'by power of the return-spring. `The same ease of operation is had in effecting the case-shifting by means `of the non-melting shin-key, it being noted (hat thework of raising the type basket is accomplished D by the retum-spring and toggles, the respective shift-keys serving merely to` control the operation. L

To suspend t'ne type basket in a floating or buoyant manner, the basket is subjected to the y 5 tension of a pair ofbalance-springs which= are suspended from a fixed portion of the machine and have their lower ends engaging the basket at suitable points.

A further feature of the case-shift mechanism, comprising a system of shift-keys and shift-lock 5 keys at each side of the machine, resides in the provision of a rock-shaft which serves to coordinate each set of keys in operation by operably joining the two toggle mechanisms, corresponding arms of the respective toggles being l0 xed to the rock-shaft to act in unison although the control of the basket-shift be eected only on the shift-key at one side of the machine.

Certain advantages are had in conjunction with the case-shift mechanism of the invention by lll providing a case-shift. stop of novel construction affording limiting means for the travel of the type-bar segment or basket operable in a soft, quiet manner to gradually and positively arrest the motion of the basket without causing any shock or noise in the machine. The case-shift stops each comprise a pad of laminations or sheets, preferably metallic,v the laminations being mounted in cantilever manner to project directly from a xed bracket upon which each pad of laminations is clampingly held. 'I'his clamp- 'ing of the laminations so compresses the pad at the region of attachment to the bracket, that the extending portions of the laminae are caused to diverge from each other so as to provideminute cushioning air spaces between the respective laminae. The two outside laminae or leaves are fabricated of spring steel, while the intermediate leaves are constructed of a relatively inert, or soft material, such as softiron. Thus, as aimember, the basket or platen, during case-shifting, moves into engagement with one of the projecting ared pads, the adjacent spring leaf is gradually sprung into engagement with the succeeding leaf, the second with the third and so forth, until the entire pad is compacted to a solid stop during which time the air between each leaf is slowly expelled to afford the cushioning action and mute any noise otherwise had.

Obviously the stop-pads offer resistance to compaction and the toggle mechanism affords a means whereby the laminae are easily compactfable by a lightforce, such as the said key returnspring, under advantage of greatly increased leverage at the time when the laminae are being compacted. Explaining it diierently, the case shift member is movable by the togglemechanism at greatly varying leverage, which leverage is relatively small or inferior during the major Part 0f the Gase-Shift movements and which leo5 verage is relatively superior, during the restoration of the case-shift member to normal-case position while the stop-pad is being compacted.

The cantilever-portion of each laminated pad is backed by an adjustable screw, threadledly carried in a-bracket extending from the machine and affords means by which the position of the typebar segment, in either extremity of case-shift motion, may be determined with accuracy, it being noted that the projecting portion of each pad, being cantilever, may bey exed to the desired stopping position.

The means for mounting and guiding the typebar segment in case-shift movement, embodies other features of the invention. The type-bar segment includes a frame vwhich journals the mentioned rock-shaft, which shaft, extending laterally toward side-plates of the machine, is provided with anti-friction rollers which function both as slidable journals for the rock-shaft, as well as guiding means for the segment in caseshifting, each roller tracking on edges of a slot in the side plate of the machine.

The upper portion of the type-bar segment is guided for case-shifting movement on a pair of ball-guide units at each end of the segment, each having a single ball therein, the ball races of each unit presenting novel arrangements to afford accurate adjustment of theguide units as well as smooth frictionless action in their guiding function. An outside ball race is adjustably carried on a side plate of the machine, being movably positioned thereon by a bolt extending from the race through the supporting member and having a wedge plate disposed between the ball race and the support, the positioning of which accurately eifects the desired adjustment. When the desired adjustment is determined. same may be secured by tightening a nut on the race bolt to clamp the Wedge plate.

The complemental ball races of each ball-guide unit are each carried on and adjacent opposite ends of the type-bar segment. Each of these races presents an elongate plate of resilient material secured at one end to a pad of the typebar segment so that a substantial length of the plate overhangs the pad in cantilever manner to yieldably engage the corresponding ball. One of these cantilever ball races is preferably backed at its free end-by a boss extending from the segment-frame to contact the back of the race, the other cantilever ball race being substantially7 unsupported at its free end in that an adjacent boss on the segment frame is spaced slightly therefrom. This spacing is at a minimum so as to back the resilient ball race against any undue ilexure which might result in momentary excessive looseness to the opposite ball-guide unit. The resilient mounting of at least one of the segment ball races presents an arrangement whereby a constant pressure is applied to the races and balls of each guide unit and serves to limit the combined pressure 'on the ball races such as may be applied in adjusting the outer race, the amount of space between the cantilever race and the segment boss being an accurate indication of the extent to which the race is being flexed at the time of adjustment. The uniformity of the pressure thus assures a smooth action of the guide units in supporting the segment in case-shifting movement.

Another feature of the invention, in conjunction with the case-shifting mechanism, is the n ovel arrangement of the shift lock pawl to cooperate With both the shift-lock .lei/eran@ th@ shift-lever in such manner as to facilitate locking and release of the case shift. The pawl is pivotally mounted on the lock-lever and is extended laterally in a lug to engage a portion of the shift-lever, suitable spring means being provvided to hold the pawl lug in constant engagement with the lock-lever member, the mentioned spring serving also to urge the pawl into locking engagement with an adjustably stationary stop on the machine. Thus it will be seen that during depression of the lock-lever in ease-shifting, the locked pawl is coactively released to locking position actuated by its spring to swing. during which movement, the pawl lug maintaining constant engagement with the shift-lever member, holds the shift-lever constantlyy but yieldably in normal raised position.

In releasing the case-shift lock by depression of the shift-lever, the reverse action takes place. The member of the shift-lever, engaging the lug of the locked pawl, gradually swings the pawl to disengage its stop and at the instant of release, a lug projecting from the shift-lever and overlying a portion of the lock-lever, engages the latter to receive the load of the type-bar basket therefrom so that the return of the case-shifting movement is controlled by the manual upward release of the shift-lever to check the effect of the type-bar segment, portions thereof being shown in section.

Figure 4 is a detail perspective View of a wedge plate forming part of the segment-frame mounting and guiding means.

Figure 5 is a fragmentary horizontal section through the segment frame illustrating the guide bearings mounting the segment for caseshift movement.

Figure 6 is a perspective view of the entire case-shift-mechanism in normal position, with the type-bar segment normally raised for lowercase printing.

Figures 7 and 8 are fragmentary perspective views illustrating the two operating positions of the case-shift mechanism; the type-bar segment having been lowered for upper-case printing;

Figure 7 illustrating the mechanism at the completion of down-shift to lock the setting by depressing the shift-lock key, and Figure 8 showing the mechanism operating to temporarily lower the segment for momentary upper-case printing by depressing the shift lever.

Figure 9 is a transverse sectional view through the group of larnnations forming the case-shift stop. A

Figure 10 is an enlarged detail view looking at the side of the case-shift stop.

Figure 11 is an enlarged front elevation of the case-shift stop, including the associated toggle and rock-shaft, and y Figure 12 illustrates in perspective the corresponding cantilever raceways of the segment mount.

The type-action illustrated in the drawings is similar to that shown and described in applicants Patent No. 2,072,878 and dated March 9, 1937. The type-action includes a system of keylevers i2, fulcrumed adjacent the lback of the machine, the key-levers being flexibly joined by links lI3 to a series of sub-levers I4 pivcted on a fulcrum-rod I5, carried in a cross-bar I6 mounted on th` side plates 'I1 comprising the frame of The sub-levers i4 actuate a system joining the free end of each sub-lever I4 to a drive arm of the type-bar I8. The series of type-bars IB are pivotally mounted in a segment 15 2| for swinging toward a common printing point on a platen 22, the latter being guided for letterspace movement, by a platen-carriage 23 riding in a trackway 24 extending between the side plates I1. f D

20, The segment 2I is mounted and guided for case-shift movement as shown more clearly in. Figures 1, 2 and 3, the segment 2I being secured to a segment-frame 25, having depending members or arms 26 each forming at their free ends bearings 21 in which a rock-shaft 28 is journaled, 4theshaft 28 extending laterally to the side plates I1 of the machine and carrying rollers 29 at the ends thereof. Y

` As will be hereinafter described in further' de- I. tail, the rock-shaft 28 accomplishes several funcytions, namely, that of co-ordinating the action vfof the two units of case-shift operating levers at the sides of the machine, and guiding the lower portion of the segment-frame during case shifting. portions of the rock-shaft 28 also engaging the case-shift stops to limit the travel of the segment 2 I. The ends of the rock-shaft carry rollers 29 which track in slots 30 in the respective side-plates I1.

The upper portion of the segment-frame 25 is mounted and guided for case-shift movement in a'pair of anti-friction bearing units 3I 32 at the respective lateral extremities of the segment frame. Each bearing unit includes a single ball or roller 33 jointy affording slight pivotal movement for the segment on the common axis delned by the respective rollers 33, as may be reured in aligning both the upper and lower guide- 50 means o f the segment to compensate for slight variations in manufacture. Each bearing unit 3 I 32 includes resilient raceway plates or leaves 34, mounted `in cantilever manner o'n the segmentframe 25, each being secured to a pad 35 offset 55 from the frame. Each raceway plate 34 extends upwardly from its mounting to afford yieldable engagement with the roller 33, which rides in a raceway 36 therein. The projected 'portion of one of the raceway plates 34 is backed by an 60 abutment or boss 31 for xed support thereon,

the other raceway plate 34 having a similar abutment 38, disposed to back theoprojected portion fio I8 by means of pull-rods I9 flexiblymounted on the main frame of the machine by pressure to the bearings pon being flexed to straight condition at assembly.. 1`

The respective bearing units 3l, 32, are each provided with complementary raceways 38 means of brackets extending from the trackway 24 to assure accurate disposition of the segment 2l and platen 22. Each raceway 39 includes a threaded stud 4I extending through the bracket and having a nut 42 thereon securing the raceway. At least one of the raceways 39 is adjustably positioned so as to regulate the pressure between the raceways and rollers of the bearings 3l, 32 and particularly to so flex the raceway plate 34 of 'bearing 32 toward the abutment 38 to assure the desired minimum spacing 49 therebetween. The bracket 40 of bearing unit 3l has its surface adjacent theraceway 39 bevelled to accommodate a wedge-plate 43 vbetween same. and the raceway 38, the wedge-plate 43 being U- 20 shaped so as to straddle the stud 4I.l Simultaneous adjustment of the bearing units 3|, 32 is afforded by the loosening of the nut 42, and thereafter driving the wedge-plate 43 upward to loosen, or downward tov tighten the bearings until the desired pressure is attained, after which the nut 42 is turned up to secure the adjustment by clamping the wedge plate 43 tightly in place.

A member of the segment frame 25. preferably the projecting portions of the rock-shaft 28, moves in a path conned by a pair of case-shift stops 44, shown more clearly in Figures 10 and 11, to limit the travel of the segment 2| in a quiet manner during case shifting. -A bracket 45 provides anchorage for a pair of co-extensive laminated pads 46 which project therefrom in cantilever manner into the path of the rock-shaft 28. The bracket 45 is secured to the main-frame sideplate I1 and is formed in an open loop to present opposed walls against which the respective pads 46 are clampingly held. The medial portion of bracket 45 has integrally formed thereon opof the same, but spaced slightly therefrom as indicated at 49 to permit limited exure of the plate 65 34. The spacev 49 being. very slight, practically positely projecting prongs 41, corresponding pairs of which align the several laminae of the pads 46, the latter being preferably clamped to the bracket 45 as by a bolt 43 passingtherethrough. The bolt 48, during assembling, is rso tightened as to compress' the anchored portions of the pad Iaminae 46, to cause the projectingV portions to be slightly flared from each other, thereby affording minute air spaces or voids between the respective laminations of the pad. As shown in Figure 9, the two outer laminae or leaves are fabricated of a resilient material such as spring` steel to withstand repeated impact and fexure and thus sustain the intermediate leaves which are preferably fabricated of a relatively inert material such as soft iron. It has been found that, by composing a stop of a plurality of members same is more effective in cushioning impact as in case-shifting and deadening any noise which may result, particularly wherein most of vthe stop elements are made of an inert material. The sound deadening -or mutingeffect is further augmented by the obviates any lateral play or disalignment of the'- segment 2l, although affording a sufficient latitude for i'lexure ofthe plate 34 to provide such yieldability as will assure smooth action of the bearings 3l, 32 during case shifting. 'I'he plates' being resilient exert constant pressure on the rollers 33 so that they are always in tight rolling contact and therefore do not drop. The yieldable raceway plate 34 may be offset angularly at a desired degree, Figure 12, so as to impart the desired flared arrangement of 4the stop leaves, which,- upon being impacted or engaged by the segment member during case-shifting, are gradually packed or compressed one against the other so as to expel the air from between the leaves. The resilient outer leaf engageable by the shaft 28vis of such slight strength as to Iiex readily when pressed without causing.. the slightest bounce or rebound to the segment. g

` The projecting pads 46, in addition to affording a cushioning stop for the segment,- also vfacilitate 75;

ro-Y

' adjustment so that the upper and lower stop positions of the segment may be positively determined to accurately locate both type cases relative to the printing line on the platen, each pad 46 being backed at its projecting end by an adjustment screw 50 abutting same. The screws 5U are threadedly carried in lugs overlying the pads 66,the lugs 5i being formed on a bracket 52 se. cured to the side plate l1.

The structure and operation of the case-shift mechanism, Figures 1, 6, 7 and 8, will now be described, the same functioning to lower the normally raised segment against the power of spring means, and inversely to permit return to raised position of the segment actuated by the spring means, by operation of the proper control keys. As aforeindicated, the rockable shaft 26, being rotatably carried on the segment-frame 25, embodies means by which the control of the shift- Akeys is imparted to the segment in case-shifting.

At each extremity, the rockable shaft 28 has associated therewith an articulated leverage-train 55, comprising a first arm 56 aixed to the shaft 28, and a second arm 51 fulcrumed at 58 on the main frame, and articulated to therst arm 56, so as to constitute a toggle joint. The fulcrum 58 comprises a rotatable eccentric bushing, Figure 11, carried on a bracket of the side plate I1 by a stud 581 by which the effective axis of the fulcrum may be adjusted to compensate for wear in the toggle-joint 55 or for other purposes. Fulcrum 58 is disposed on a, line defining the path of travel of the segment-frame 25 in case-shifting and below same, so that when the arms 56 and 51 are aligned, one with the other, the segment 2| and associated type-bars I8 are maintained in raised position thereby. As arm 51 is caused to swing, the toggle-joint or leverage-train 55 is unlocked and folded to permit lowering of the segment assembly.

The rotation of arm 51 is controlled by operation of one of the shiftkeys, a return spring 59 acting always to restore the mechanism to normal with the segment raised. The arm 51 has a drive arm 511 extending angularly therefrom, flexibly joined by a link 66 to an arm 6l of a shiftlock lever 62. Shift-lock lever 62 is fulcrumed on the sub-lever fulcrum-rod I5 and extends forwardly of the machine, terminating in a shift-lock key 63. A similar shift-lock lever 62 is provided at each side of the machine, the same being operably connected to a corresponding toggle 55 by its link 60. Each shift-lock lever has associated therewith a shift-lever 64, also fulcrumed on rod l5 and carrying-a shift-key 65 at its free end. Shift-lever 64 includesl a lug 66 extending therefromto overlie the lever 62 so that upon depressing the shift-lever 64, the lock-lever will move therewith, although the shift-lock lever 62 may be actuated independently oi the shiftlever 64. 'Ihe return spring 59 is anchored on the machine, its end being joined to a depending member of the lock-lever arm 6I whereby to urge the toggles 55 to aligned condition so that same hold the segment raised, the toggles 55 being stopped at aligned setting by the engagement of the lock-lever- 62 with a guide-plate 14 or other member of the machine.

It will be noted from the foregoing that the rockable shaft 28, by operatively connecting the arms 56, functions to coordinate the actions of both of the toggles 55 whereby lowering or raising power thereof is imparted equally to both extremities of segment 2 I, Figure 6. Since each toggle 55 is operably associated with a corresponding shift-lock lever 62, the actions of the respective levers. 62 are also coordinated. The rockable shaft 28, connecting the two arms 56 of the toggles 55 together, is rotatably carried in the segmentframe 25, at a relatively high elevation in the machine, thereby aiording adequate space underneath for mechanisms such as the rearwardly extending key-levers.

A shift-lock 61 is provided to lock lever 62 down, the lock 61 being so associated with the respective shift-levers 62, 64, that when both levers move in unison, as by depressing4 lever 6 I, the lock is ineffective, and inversely, as the shift-lock lever 62 moves independently of the shift-lever 641, the lock 61 is allowed to engage. Lock 61 comprises a lock pawl 66 presenting a bell-crank pivotally mounted on the lock lever 62 and urged by a spring 69 to swing into locking engagement with a detent 1D, but normally prevented from so doing by thg engagement of a lateral lug 1l of pawl 68, with a pad 12 on the shift-lever 66. y

Figure 7 illustrates the operation of the mech anism in locking the segment down by depressing the lock-lever 62, the lock pawl 68 having been allowed to swing into engagement with the detent by the tendency of the lug 'H to move away from the pad 12, thereby releasing the pawl 68 toy permit its spring 69 to actuate the pawl into engagement with the detent 10. This action is due to the relative positions of the lock-lever 62 and the shift-lever 66 which, during depression of the lock-lever 62, are moved apart and consequently release the pawl 68 to engage the detent.

In releasing the lock 61, the reverse operation takes place, the lock being released by depressing the shift-lever 66 during which its pad 12, engaging the lateral lug 1l, swings the pawl 68 free of the detent 10, the pawl releasing at the instant the lug 66 reaches the depressed lock-lever 62.

the segment 2l returns to its normal raised posi-y tion. Y

A particular advantage of the novel case-shit lock 61 is that both the shift-lock key 63 and the shift-key 65 are at a'constant elevation at the time the function of either is required.' As isusual in case-shift mechanisms, the shift-lock key. is locked down during the interval at which the segment is locked down for upper-case printing, but, in such machines the shift-key is also lowered. In the present invention the shift-key 65 remains at normal position although the shift-lock key '63 be depressed and the operator may therefore accustom herself to nding the shift-key 65 at the same elevation at all times. Furthermore, the work of releasing the pawl 68 from its detent 10 is minimized since the releasing is effected during the entire down-stroke oi the shift-lever 64. This improved operation makes for an appreciably light touch and smooth action of the shift-lever 64 in its unlocking function, the same acting without jar, by assuming the load of thesegment mass, eiecti-ve by the return spring 59, at the instant of release of lock 61.

The respective actions of each shift-lever 64 are co-ordinated by a rockable bail 15 trunnioned on brackets 16 adjustably alixed to the guide-plate 14 by screws 11 disposed in slots therein. The rockable bail 15, extending laterally of the machine, includesl a forked arm 18 at each end thereof which engages a pin 19 carried on a member 80 of the shift-lever 64. It will be noted that the detent 10, co-operating with the lock 61, forms part of the bracket 16, so that both the detent and the Journal of the bail 15 are adjustable simultaneously. In the event that lowering of detent is required in regulating the shift mechanism, the lower locked position of lever 62 necessitates a greater drop for shift-lever 64 to release the lockv61, which increase is accommodated by lowering the bracket 16.

The work of the return springs 59, in restoring the type-bar segment 2| to normally raised position in co-operation with the toggles 55, is-

gageablevwith an escapement-wheel |05.

supplemented by balancing springs 82 which have the elect of resiliently sustaining the segment 2|. Springs 82 are anchored at their upper ends to a fixed portion of the machine and` are secured to studs 83 projecting from the segment-frame 25, Figures 3 and 6. The balance springs 82 may be so tensioned as/to yieldably sustain the entire mass of the type-bar, basket, the weight of which is supported by the segment-frame 25, the effect being to substantially reduce the eiort required to move the segment` in case-shifting.

The letter-feed escapement-mechanism illustrated is similar to that used in the standard noiseless Underwood machines except that certain changes are embodied therein, to adapt the mechanism for association. with the other improvements shown. 'I'he escapement-mechanism, Figure 2, comprises an arcuate universal bar 9|, arranged on the segment 2| for engagement by a heel 92.0f`each type-bar I6 which, during swinging, engages the universal bar 9|- to actuate the letter-feed escapement. The universal bar 9| includes side arms 93 pivoted to a rock-frame 94 journaled at 95 in brackets 96 extending rearwardly from the segment 2|. The rock-frame 94 co-operates with a tongue 91 of the universal bar for sliding motion relative to the segment 2|. A link 98, flexibly connected to the rock-frame 94, threadedly carries adjustable collars 99 engageable with a dog rocker |00 through which the link 98 projects. The dog rocker |00 is pivoted for rocking motion vat |0| on a bracket |03 hung from the carriage guideirame 24 and has a member |02 extending forwardly and carrying at its free end a springbacked p'awl |03 and a stop-dog |04, each en- The escapement-wheel |05 is rotated coactively with the endwise travel of the platen-carriage 23, wheel |05 being carried on a shaft |06 including a pinion |01 in mesh with a gear rack |08 on the carriage 23.

YIn inactive position, the pawl |03 holds the platen-carriage 23 stationary against the power of its travel spring, not shown, the pawl |08 being normally engaged in the teeth of the escapement-wheel |05. As the type-bar heel 92 strikes the universal bar 9|, the link 98 is pulled by action of the rock-frame 94 and the dog-rocker member |02 is oscillated so that the pawl |03 moves free of the wheel |05, allowing the latter to rotate anamount equivalent to one letterspace, the rotation fof wheel |05 being limited by the action of stop dog |04 which,` being pivotally mounted, swings a limited degree while engaged byvheel |05 to stop same at the completion of la* letter spacing.- As the ltype-bar I6 drops back, the dog-rocker |0|'is restored by a spring H0. Pawl |03 is returned to sition engaging the tooth of wheel |05 being released by dog |04. Pawl |03 is pivoted to permit return of the platen carriage to the right, pawl |03 ratcheting over wheel |05,J now rotating reversely. l'I'he letter-feed mechanism may also be operable by a spacer-key in the usual manner.

Referring to the provision of shift-key mechanism at each side of the machine, it will be noted that at the depression of either shift-lock lever 62 relatively to its companion shift-lever 64,

the other shift-lock lever 62 isalso depressed relatively to its companion shift-'lever 64, since both of said levers 62 are operatively connected by means of the cross-shaft 28. Hence both of the locking pawls 61 are caused to move to effective position under their detents 10, as in Figure 7, at the depression of either shift-lock lever 62. The depression of either shift-lever 64 for the purpose'of releasingthe companion locking pawl 61 also serves, by means of the crossshaft 15, to depress the other shift-lever 64 thereby to release also the locking pawl 61 associated with the latter.

It will be seen that in the restoration of the parts to normal (lower-case) position the compacting of the upper laminated stop-pads 46 against the stop-screws 50 is effected by the force of the restoring springs 59. Said` spring force may be small, and hence the springs 59 may be light, since said springs work through the mechanical-leverage-increasing toggles 55 to squeeze and `compact the upper stop-pads` 46. In lowering the shift-frame 25 to upper-case typing position by depressing the case-shift keys a light nger-pressure upon said keys avails to compact the lower laminated stop-pads 46 against the stop screws 50. Thus, case-shifting may be -eected by a light, easy finger-touch upon the case-shift keys.l

In typewriting machines it is of utmost importance to accurately arrest the case shifting body or member, so that all characters whether of the lower or upper case variety will be printed in exact alignment. The laminated stop pads 46 herein employed prevent all possible overthrow of the shiftable member by their full compaction to a solid non-yielding final stop. The togglesy 55 when being straightened squeeze said laminations to full compaction in lower case typing position so that the shifting segment will be accurately located relative to the frame and the printing point. The return spring-power to drive the segment to normal case positionat the V release of the shirt key need be but very light because of the leverage-increasing toggle device that squeezesthe laminations to a solid pack. The return springs 59 are also eiective to lock and retain said toggles 55 in straightened position to retain the segment against the tendency of the laminae toseparate. Since the return spring 59 may be extremely light, itfollows that of two case-positions to the other, stop-pad means comprising slightly spaced laminae arranged to be solidly compacted against .said frame by the movement of said membefto at least one case normal pO- position, said laminae offering resistance to compaction and serving to noiselessly arrest and locate said member, and means for moving said member from either one of said case-positions to the other, the last said means including devices eiective during at least one of said movements for providing greatly increased leverage while compacting the laminae.

2. In a typewriting machine, having a main frame and a member mounted for movement'l from either of two case-positions to the other, stoppad means comprising slightly spaced laminae arranged to be compacted against said frame by the movement of said member to at least one case-position, said laminae oiering resistance to compaction and serving to noiselessly arrest and locate said member, and means for moving said member to either case-position, said means including devices adapted to assume a dead center position in moving said member to at least one case-position to thereby move said member atincreased leverage while compacting said laminae and provide for the locking of said member.

3. A typewriting machine as set forth in claim .2, comprising, means for varying the position to which said member is movable by movement of said devices to saiddead center position.

4. In a typewriting machine, having a main vframe andv a member mounted for movement from either of two case-positions to the other, stop-pad means comprising slightly spaced 1aminae arranged to be compacted against said frame by the movement of said member to at least one Case-position, said laminae offering resistance to compaction and serving to noiselessly arrest and locate said member, and means comprising a toggle-linkage, pivotally connected with said member and said frame for moving said member to either case-position, vand adapted to assume a straight-line position in moving said member to at least one case-position to thereby move said member atincreased leverage while compacting said laminae and to provide for the locking of said member.

5. A typewriting machine as set forth in claim 4, comprising, means for varying the position to which said toggle-linkage is able to move said member in assuming said straight-line position.

6. In a typewriter having a main frame and a member mounted for movement from either of two case-positions to the other, stop-pad means comprising' superposed elongate leaves of hard resilient material extending from a support and relatively spaced in a stop region,4 to stop said member in its movement to at least one of said case-positions, by being compacted against said frame, said leaves offering considerable resistance to compaction and serving in being compacted to noiselessly arrest and locate said member, and means for moving said member from either one of Vsaid case-positions to the other at greatly varying leverage which is relatively small during the major `part of said case-shift movements, and relatively vastly superior, during at least one of said case-shift movements while compacting said leaves against the said resistance.

7. In a typewriter having a main frame and a member mounted for movement from either of two case-positions to the other,'stoppad means comprising spaced laminae arranged to be compacted against said frame by the movement of said member to either case-position, said laminae oiering resistance to compaction, and serving to noiselessly arrest and locate said member, a case-shift key, a spring, and membermoving means operable by said key to move said member to one case-position and by said spring,

at the release of said key, to move said member to the other case-position, comprising, a leverage changing device, providing for inferior leverage movement of said member by said spring during a major part of the shift-movement and for vastly superior leverage movement of said member by said spring while said laminae are being compacted.

8. In a' typewriter having a main frame and a member' mounted for movement from either of two case-positions to the other, stop-pad means comprising spaced laminae arranged to be compacted against said frame by the movement of said member to either case-position, said laminae offering considerable r-esistance to compaction and serving in being compacted to noiselessly arrest and locate said member, a case-shift key, a spring, and member-moving means operable by said key to move said member to one case-position and by said spring, at the'release of said key, to move said member to the other rase-position, comprising, a toggle device linked to said frame and said member to assume respectively a brokenline position in being moved to said one caseposition and a straight-line position in being moved by said spring to the said other caseposition, whereby said spring operates under advantage of greatly increased leverage while said laminae are being compacted against said frame and whereby said member will be locked against movement, except by operation of said key.

9. In a typewriter, having a main frame anda member mounted for movement from either of two case positions to the other, means to stop said member in said case-positions,including, an

. upper-case and a lower-case stop on the frame associated respectively with an upper-case and a lower-case stop on said member, a plurality of superposed, inherently spaced, hard leavesinterposed between ysaid associated stops, the said leaves providing cushions that are compactable between the stops to noiselessly, yet positively arrest said member, means to individually adjust one of every two associated stops toward or away a member mounted for movement from eithery one of two case-positions to 'the other, at least one stop-pad for limiting each one of the said case-shift movements, said stop-pads comprising superposed leaves of hard resilient material shackled to the frame near a stopping-region -and inherently slightly spaced relative to each other at the said stopping region, a back-stop for each one of the said pads, adjacent the said stopping region, on the said frame, means to inone of said case-shift movements for providing j greatly increased leverage While compacting the leaves.

WILLIAM F. HELMOND. 

